Interleaved PWM with discontinuous space-vector modulation

This paper describes the effect of interleaved discontinuous space-vector m odulation (SVM) in paralleled three-phase systems using three-phase pulsewi dth modulation (PWM) rectifiers as an example. At the discontinuous point o f the SVM, the phase shift between the switching signals of the paralleled modules generates a zero-sequence excitation to the system. Because the con ventional control in a balanced three-phase system,vith only dq channels ca nnot reject this disturbance, a heat-frequency circulating current,will dev elop on the zero axis. Based on this observation, a SVM without using zero vectors is used to eliminate the cause of pure zero-sequence current for pa rallel operation. Using this SVM, the circulating current is observable in dq channels. It can be suppressed dynamically by strong current loops of po wer-factor-correction (PFC) circuits. The concept is verified experimentall y on a breadboard system.